Something Lou Gerstner, former CEO of IBM, once said has stuck in my head: "Never let anyone own your schedule." It's simple and obvious, yet genius.

Over the years, whenever I didn't follow this advice, I was stressed and unproductive. Gradually I learned that planning and following a routine makes a huge difference in how I feel and what I get done. Here are some of the things that help me manage my schedule that you may find helpful:

1. Create a routine

No matter what you are working on, create a routine. Block times for specific activities, and stick with the plan. Turn your calendar into a bunch of blocks, and put activities into those blocks. Whatever is not planned, you don't do. If you want free time, plan it.

Your routine may change through the year, but at any given time it's better to have a plan. For example, if you are working on launching a company, and need to do customer discovery, coding and hiring, then prioritize and block specific times for each activity.

Here is a sample calendar I made that illustrates some of the concepts and ideas from this post.

2. Group meetings and calls into blocks

For example, if you need to have outside meetings, block two and a half days a week for those meetings, and go to the outside meetings only during those times. Do the same thing for in-office meetings. This way you are not only creating a chunk of time for meetings, you are also creating other blocks of time that you will be able to important work. Do the same thing with calls, and book them all back to back.

3. Optimize time for different meeting types

Personally, I am now a big fan of 30-minute meetings and 10-minute calls. I think 10-minute calls are a great way to initially connect with someone or give someone quick advice. You can do a Google Hangout or Skype if you prefer to see the person instead of just hearing them. The reason 10-minute calls work is because people skip BS and get to the point. Try it. Ten minutes is actually a lot of time, if you focus. I prefer to do these calls on Fridays, when I am usually working from home.

I am not a big fan of introductory coffee meetings, lunches and dinners. I am a huge fan of coffee and meals with people I already know. Those meetings are typically productive and fun, but the first time you are meeting someone, it's more productive to do a call or an actual 30-minute meeting in the office.

Here are the types of meetings you might want to book:

30-minute meeting in the office to get to know someone or catch up

45-minute meeting outside of the office. Allow 15 minutes for travel.

10-minute call to help someone who needs advice

15-minute daily standup -- great for startups and engineering teams

30-minute weekly staff meeting

Whatever meetings you hold, group them into blocks depending on your particular schedule. If you feel like a particular type of meeting needs more or less time, then adjust the block accordingly.

4. Use appointment slots

There is a great feature in Google Calendar called Appointment Slots. It allows you to book a chunk of time, and then split it into pieces. For example, I can book three hours of outside meetings and then split it into three meetings -- one hour each. Or I can book one hour of calls and split it into six calls at 10 minutes each. There is also a bunch of specific tools, such as doodle, that do that too.

The next step is to create bit.ly links for different blocks of time.You can have a link for your outside meetings, another link for 30-minute inside meetings and yet another one for 10-minute calls. You then share these links, and they can book the time with you. I've done this with Techstars candidate companies and it was amazingly effective. It minimized the back and forth on email and saved a ton of time for me and the companies.

This won't work with everyone, because some people may find this rude. In any case, if you are not comfortable sending the link to a someone, then you can use your own appointment slots, suggest a few meeting times, and then book the specific slot yourself.

If you are asking someone to meet, always propose several specific alternative times such as Tuesday at 4:30 p.m. or 5 p.m. on Wednesday. David Tisch gave a great talk that covers scheduling meetings and many more basics of communication.

5. Block time for email

This is the most important tip in the whole post. Email will own you unless you own it. To own your email you must avoid doing it all the time. To do that you need to schedule the time to do your email. It is absolutely a must. In fact it is so important that I wrote a whole entire post about managing email.

6. Plan your exercise and family time

Unless you put it on the calendar, it won't get done. Well, that applies to your exercise and time with your family. Whether you go in the morning, afternoon or evening, do it three times a week or every day, put exercise time on the calendar. My friend and mentor Nicole Glaros makes it very clear that her mornings, until 10 a.m., belong to her. She hits the pavement or the gym, depending on the weather, and rarely deviates from her routine.

The same applies to planning time with your family and significant others. If you are a workaholic like me, you will end up stealing time from your family unless you book it in advance and train yourself to promptly unplug. Many people in the industry have talked about planning family time. My favorite is Brad Feld, who talks about it a lot.

7. Actually manage your time

I think about my time a lot. I think about where it goes. I think about where can I get more of it, and how to optimize it. When I was running GetGlue, I had an assistant who was managing my time. She was awesome. But when I joined Techstars, I decided that I will manage my calendar myself. I have to confess that I am happy about this decision.

I find myself thinking about what I am doing, who am I meeting with and why a lot more. I meet with a lot of people every week. My schedule is particularly insane during the selection process. Yet, because I manage my calendar, follow a routine, plan meetings in blocks and use appointment slots, I find myself less overwhelmed and less stressed.

Taking ownership of my calendar and planning my days and weeks made me a happier and more productive human. I hope this post helps you get there too.

I would love to hear your productivity tips. How do you manage your time? How do you handle your calendar? What tools do you use? Please share in the comments section below.

This article was written by a member of the AlleyNYC contributor network. AlleyNYC is one of the world’s largest innovation hubs, helping foster the growth of startups in its flagship location in New York City. Entrepreneur Media is a partner and investor in AlleyNYC. If you would like to learn more about AlleyNYC and how to apply for membership visit here.